Can't see shared libraries in iTunes

i've been reading many threads on iTunes music sharing issues but none seem to address my problem. i can't see any shared libraries in itunes, though i'm sure there are some in my local network. i just switched to mac and everybody around me has windows, i don't know if that's part of the problem.

1. the option to look for shared music is checked.
2. other users can see and listen to my library, and can see each other, so i guess it's not an issue of there not being any other shared libraries in my network.
3. in fact, i can see limewire users in the shared music panel other iTunes users can see too, but i can't see them!!
4. I have enabled my firewall to allow for iTunes music sharing. The windows users with iTunes in my network are not even firewalled.

is there a very dumb mistake i'm making here?? if anyone has an idea please let me know... i'm getting very lonely music-wise here!
thanks!!!
tato.

Since I see this is an old thread, but was experiencing the same problem in 2010...

AND since google referred me here (which i believe many others would be too) here is how I fixed the problem on a Toshiba that I was using in regards to not seeing shared libraries on my network.

Of course check your firewall first (turn it off to do a test) with other computers you have access to.

Second let iTunes do a diagnostic on itself to see if there were problems with the program itself (which, for my instance, found that there were none). Tried a reinstall just to be sure.

And finally, figured out that it had to be a hardware type issue, primarily in regards to drivers for my wireless LAN card. Went to the toshiba website with my computer's model number and downloaded the drivers, installed, and SUCCESS!